Publication Date:
2020-12-14
Description:
Observations of very low amounts of precipitable water vapor (PWV) by means of the
Ground-Based Millimeter wave Spectrometer (GBMS) are discussed. Low amounts of
column water vapor (between 0.5 and 4 mm) are typical of high mountain sites and polar
regions, especially during winter, and are difficult to measure accurately because of the
lack of sensitivity of conventional instruments to such low PWV contents. The
technique used involves the measurement of atmospheric opacity in the range between
230 and 280 GHz with a spectral resolution of 4 GHz, followed by the conversion to
precipitable water vapor using a linear relationship. We present the intercomparison of this
data set with simultaneous PWV observations obtained with Vaisala RS92k
radiosondes, a Raman lidar, and an IR Fourier transform spectrometer. These sets of
measurements were carried out during the primary field campaign of the Earth Cooling
by Water vapor Radiation (ECOWAR) project which took place at Breuil-Cervinia
(45.9N, 7.6E, elevation 1990 m) and Plateau Rosa (45.9N, 7.7E, elevation 3490 m),
Italy, from 3 to 16 March 2007. GBMS PWV measurements show a good agreement with
the other three data sets exhibiting a mean difference between observations of 9%. The
considerable number of data points available for the GBMS versus lidar PWV
correlation allows an additional analysis which indicates negligible systematic
differences between the two data sets.
Description:
Published
Description:
D14314
Description:
1.8. Osservazioni di geofisica ambientale
Description:
JCR Journal
Description:
reserved
Keywords:
millimeter wave spectroscopy
;
column water vapor
;
01. Atmosphere::01.01. Atmosphere::01.01.01. Composition and Structure
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
